max-lines, fix parser

src/ftracetool.c

@@ -34,6 +34,8 @@ struct ftt_mapping
     struct ftt_mapping *next;
 };
 
+static int g_max_lines = 0;
+
 static struct ftt_mapping *gs_mappings;
 
 static struct ftt_mapping *parse_mapping(const char *const raw_str)
@@ -92,6 +94,16 @@ static int embed_mappings(sexp ctx)
     sexp_gc_release2(ctx);
 }
 
+static int embed_options(sexp ctx)
+{
+    sexp_gc_var2(option_name, option_value);
+    sexp_gc_preserve2(ctx, option_name, option_value);
+    option_name = sexp_intern(ctx, "*max-lines*", -1);
+    option_value = sexp_make_fixnum(g_max_lines);
+    sexp_env_define(ctx, sexp_context_env(ctx), option_name, option_value);
+    sexp_gc_release2(ctx);
+}
+
 static void show_version()
 {
     printf("ftracetool v%s\n", VERSION_STRING);
@@ -321,22 +333,13 @@ static int parse_ftrace_entry(const char *str,
                               char **args,
                               size_t *args_num)
 {
-    // skip whitespaces
-    while (isspace(*str))
-    {
-        str++;
-    }
-    if (!*str)
-    {
-        return ER_PARSE_ERROR + 1;
-    }
     if (*str == '#')
     {
         return ER_COMMENT;
     }
 
     char *out = comm_buf;
-    while (*str != '-')
+    for (size_t i = 0; i < 16; i++)
     {
         if (!*str)
         {
@@ -381,7 +384,7 @@ static int parse_ftrace_entry(const char *str,
     }
 
     // skip whitespaces && flags
-    while (isspace(*str) || isalpha(*str))
+    while (isspace(*str) || isalpha(*str) || *str == '.')
     {
         str++;
     }
@@ -512,25 +515,23 @@ sexp_parse_ftrace_entry_stub(sexp ctx, sexp self, sexp_sint_t n, sexp arg0)
     char *frac = dot + 1;
     double timestamp = atol(timestamp_buf) + atol(frac) / 1000000.;
 
-    sexp prev = SEXP_NULL;
+    sexp_gc_var5(prev, head, res, tmp, data);
-    sexp head = SEXP_NULL;
+    sexp_gc_preserve5(ctx, prev, head, res, tmp, data);
     for (ssize_t arg_num = args_num - 1; arg_num >= 0; arg_num--)
     {
         head = sexp_cons(ctx, sexp_c_string(ctx, args[arg_num], -1), prev);
         prev = head;
         free(args[arg_num]);
     }
+    tmp = sexp_cons(ctx, head, SEXP_NULL);
+    tmp = sexp_cons(ctx, data = sexp_c_string(ctx, probe_id_buf, -1), tmp);
+    tmp = sexp_cons(ctx, data = sexp_make_flonum(ctx, timestamp), tmp);
+    tmp = sexp_cons(ctx, data = sexp_make_fixnum(pid), tmp);
+    tmp = sexp_cons(ctx, data = sexp_c_string(ctx, comm_buf, -1), tmp);
 
-    return sexp_cons(
+    res = tmp;
-        ctx,
+    sexp_gc_release5(ctx);
-        sexp_c_string(ctx, comm_buf, -1),
+    return res;
-        sexp_cons(ctx,
-                  sexp_make_fixnum(pid),
-                  sexp_cons(ctx,
-                            sexp_make_flonum(ctx, timestamp),
-                            sexp_cons(ctx,
-                                      sexp_c_string(ctx, probe_id_buf, -1),
-                                      sexp_cons(ctx, head, SEXP_NULL)))));
 }
 
 static int register_lookup_symbol_in_file(sexp ctx)
@@ -680,6 +681,7 @@ static int do_execute_script(const char *const filename)
     sexp_load_standard_env(ctx, NULL, SEXP_SEVEN);
     sexp_load_standard_ports(ctx, NULL, stdin, stdout, stderr, 1);
     embed_mappings(ctx);
+    embed_options(ctx);
 
     sexp_gc_var1(filename_obj);
 
@@ -743,6 +745,11 @@ int main(int argc, char **argv)
             show_symbols_in_file = true;
             break;
         }
+        case 'l':
+        {
+            g_max_lines = atoi(optarg);
+            break;
+        }
         case 'm':
         {
             struct ftt_mapping *const mapping = parse_mapping(optarg);

src/ftracetool.scm

@@ -9,12 +9,13 @@
   (let ((pair (assoc key *ftt-mappings*)))
     (if pair
         (cdr pair)
-        (raise (string-append "No mapping: " key)))))
+        #f)))
 
 (define (mapping-int key)
   (let ((value (mapping-str key)))
-    (when value
+    (if value
-      (string->number value))))
+        (string->number value)
+        #f)))
 
 (define (with-append-to-file file thunk)
   (let ((old-out (current-output-port))
@@ -204,64 +205,44 @@
                          (string-cursor-next x (string-index x #\=))
                          (string-cursor-end x))) raw-args)))
 
-(define (read-trace-events-from-file filename)
+(define (read-trace-events-from-file filename max-lines)
-  (let ((rx (regexp '(:
+  (reverse
-                      (+ whitespace)
+   (call-with-input-file filename
-                      ($ alnum (+ (~ "-")))
+     (lambda (p)
-                      "-"
+       (let loop ((line (read-line p))
-                      ($ word)
+                  (events '())
-                      (+ whitespace)
+                  (n 0))
-                      "["
+         (if (or (eof-object? line)
-                      (+ num)
+                 (if max-lines (> n max-lines) #f))
-                      "]"
+             events
-                      (+ whitespace)
+             (begin
-                      (+ (~ whitespace))
+               (let ((match (parse-ftrace-entry line)))
-                      (+ whitespace)
+                 (if match
-                      ($ (+ (or num ".")))
+                     (begin
-                      ":"
+                      (let* ((comm (list-ref match 0))
-                      (+ whitespace)
+                            (pid (list-ref match 1))
-                      ($ (+ (or alnum "_")))
+                            (timestamp (list-ref match 2))
-                      ": ("
+                            (probe-name (list-ref match 3))
-                      (+ (~ ")"))
+                            (args (list-ref match 4))
-                      ")"
+                            (trace-event (make-trace-event timestamp probe-name pid args)))
-                      ($ (+ any))
+                       (loop (read-line p) (cons trace-event events) (+ 1 n))))
-                      ))))
+                     (loop (read-line p) events n))))))))))
-    (reverse
-     (call-with-input-file filename
-       (lambda (p)
-         (let loop ((line (read-line p))
-                    (events '())
-                    (n 0))
-           (if (or (eof-object? line)
-                   (> n 1000))
-               events
-               (begin
-                (let ((match (parse-ftrace-entry line)))
-                  (if match
-                    (let* ((comm (list-ref match 0))
-                           (pid (list-ref match 1))
-                           (timestamp (list-ref match 2))
-                           (probe-name (list-ref match 3))
-                           (args (list-ref match 4))
-                           (trace-event (make-trace-event timestamp probe-name pid args)))
-                      (loop (read-line p) (cons trace-event events) (+ 1 n)))
-                    (loop (read-line p) events n)))))))))))
 
 (define (find-subprobe probe-name subprobes)
   (find (lambda (x) (equal? probe-name (ftrace-probe-name x))) subprobes))
 
 (define (ftrace-process subprobes)
+  (let ((max-lines (if (> *max-lines* 0) *max-lines* #f)))
     (with-output-to-file "/sys/kernel/tracing/events/uprobes/enable"
       (lambda ()
         (display "0")
         (newline)))
-    (let ((events (read-trace-events-from-file "/sys/kernel/tracing/trace")))
+    (let ((events (read-trace-events-from-file "/sys/kernel/tracing/trace" max-lines)))
       (for-each
        (lambda (event)
          (let ((probe (find-subprobe (trace-event-probe-id event) subprobes)))
            (when probe
-             ((ftrace-probe-process-entry-handler probe) event)))
+             ((ftrace-probe-process-entry-handler probe) event)))) events))))
-         ) events)))
 
 (define (tracing-probe ctx install remove process)
   (make-probe (lambda () (install ctx))